This might seem odd, as corrosion requires oxygen and moisture and both are absent in space. But corrosion does occur in space, but not due to oxygen and moisture but due to radiation!! Also there is presence of atomic oxygen. This is extremely dangerous to some materials, while harmless to others.
In space, high-energy ultraviolet light shatters the molecules into highly reactive
oxygen atoms that can corrode the materials spacecraft are made of. The polymer
films and silver connectors used in solar arrays are particularly
vulnerable.
The space station and many satellites orbit between 150 and 700 kilometers
above the Earth’s surface. This is close enough to the edge of the atmosphere
for the concentration of oxygen atoms to reach up to 10^10 atoms per cubic
centimeter. The speed of the spacecraft—about 8 kilometers per
second—means it hits up to 10^16 atoms per square centimeter per
second.
The process of space corrosion is being actively investigated. One of the efforts aims to design a sensor based on zinc oxide, able to measure the amount of atomic oxygen in the vicinity of the spacecraft; the sensor relies on drop of electrical conductivity of zinc oxide as it absorbs further oxygen.
Many plastics are considerably sensitive to atomic oxygen and ionizing radiation. Coatings resistant to atomic oxygen are a common protection method, especially for plastics. Silicone-based paints and coatings are frequently employed, due to their excellent resistance to radiation and atomic oxygen. However, the silicone durability is somewhat limited, as the surface exposed to atomic oxygen is converted to silica which is brittle and tends to crack.
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